Add ability to show metadata when editing CTL code

When editing complex CTL code in Reformat, it is not possible to have a look at metadata - trying to switch to visual mode will just display a warning.
Please implement functionality to allow looking at input/output metadata even while editing the code. This can be done for example by just rearranging how the "tabs" work in the dialog. Instead of switching the whole layout between visual/code, switch just the middle part. A quick mock-up attached.

The goal is to be able to see (and search) in metadata even while working with the code without having to close the dialog, open meta and then go back to the code. Nothing fancy is needed - for example the metadata does not have to support highlighting of the used fields, although it would be nice to have that available as well.